The original bi-optic laser scanners were typically designed to have a single laser light source along with its detector, collector and electronics located under the horizontal platen with only the mirrors required to scan in the vertical behind the vertical platen. However, in an effort to maximize scanner performance, the bi-optic barcode scanners of retail checkout terminals have evolved over the years into rather complex devices with multiple laser light sources, collectors, detector assemblies, mirrors and electronics. These components are typically located behind both horizontal and vertical platens from which the optical codes are read.
In an attempt to produce a combined laser and imaging scanner a camera has been placed behind the vertical platen. However, in order to provide the necessary contrast to read an optical code it is necessary to provide flashing LED light sources behind the platen. Placing these LEDs behind the vertical platen, results in the operator of the checkout terminal being located directly in the line of site. Consequently, this arrangement can result in operator eye fatigue, headaches, and even the onset of a seizure if the operator is susceptible to them.
Another issue with current combined laser and imaging scanner located in the vertical window, is that there are no means by which the operator can easily determine if the barcode is aligned to the field of view of the imaging scanner. The geometry of current imaging scanners is such that the barcodes are scanned and imaged on either the underside of an object or on the side of the object remote from the operator. This makes it very difficult for the operator to align the barcode with the camera which can lead to incomplete or blurred images of the barcode and incomplete or inaccurate decoding of the image of the barcode.
Today's high performance bi-optic scanners have six sided, omni-directional, high speed scanning capabilities. That is, no matter which side or what angle the barcode is oriented on an item, the scanner has the capability to decode it at scan speeds equal to or greater than cashier's scanning capabilities. For the scanner to have this capability, the horizontal window must be large enough to accommodate the plethora of laser lines and angles. These large, horizontal windows must resist scratching and breaking in the harsh retail environment, and are therefore made out of expensive materials such as Sapphire or Diamond Like Carbon (DLC) coated glass. The horizontal window is therefore the most expensive component in the scanner. The vertical window imager does not allow the scanner designer the opportunity to significantly reduce the cost of the scanner since the cost of the components in the vertical window are small compared to cost of the components in the horizontal window.
The combining of an imaging scanner along with a laser barcode scanner reduces the opportunity for fraudulent transactions where an operator scans a low priced or non-restricted item such as a package of gum, and passes a high priced item or a restricted item such as a cell phone as alcohol to the customer, so called “sweethearting”. The imaging scanner can be used to correlate the laser scanned barcode with an image of the item to reduce the opportunity for such “sweethearting”.
Also, the imaging scanner can be used for produce recognition, for example to distinguish between a pear and an apple when they are placed adjacent the window so that the price of loose items can be accurately calculated with minimum operator intervention.